Prevalence of chronic obstructive lung disease in Korea using data from the fifth Korea national health and nutrition examination survey

Associations between different body mass index and lung function impairment in Chinese people aged over 40 years: a multicenter cross-sectional study

OBJECTIVE

The aim of this study was to explore the associations between different body mass index (BMI) levels and different lung function impairment (LFI) in Chinese people aged over 40 years.

METHODS

We used a multi-stage stratified cluster random sampling method to investigate 3000 residents aged over 40 years from 5 areas in Hubei province of China in 2019-20. The data on questionnaire, physical measurements, and spirometry of the participants were collected. The associations of different BMI levels with different LFI were analyzed using multivariate logistic regressions after complex weighting. The spirometry data were analyzed using one-factor analysis of variance (ANOVA), and post-hoc was performed using the least significance difference (LSD)-t test.

RESULTS

A total of 2860 subjects were included. The prevalence (95%CI) of obstructive lung disease (OLD), restrictive lung disease (RLD), mixed lung disease (MLD), chronic obstructive pulmonary disease (COPD), COPD mild, and COPD moderate/severe/very severe were 24.1% (95% CI: 22.2-26.2), 11.6% (95% CI: 10.3-12.9), 4.0% (95% CI: 3.3-4.8), 12.6% (95% CI: 11.0-14.1), 7.2% (95% CI: 6.0-8.4), and 5.3% (95% CI: 4.3-6.4) respectively. After multivariate adjustment, the risk of OLD, COPD, and COPD mild decreased with the increment of BMI levels (both P for trend < 0.05). When compared to the normal weight group, the overweight group and obese group were at lower risk of experiencing OLD than normal group, the ORs were 0.77 (95% CI: 0.59-0.99) and 0.59 (95% CI: 0.40-0.86) respectively. The obese group was at lower risk for people with COPD mild (OR: 0.42, 95%CI: 0.21-0.85). Participants in underweight group were more likely to experience COPD and COPD moderate/severe/very severe, the ORs were 2.82 (95% CI: 1.07-7.39) and 3.89 (95% CI: 1.28-11.87) respectively.

CONCLUSION

Higher BMI levels were associated with an decreased risk of OLD and COPD. Obesity had a protective effect on lung function in OLD patients and COPD patients. However, there was no significant difference in RLD and MLD prevalence between different BMI groups.

Recent Prevalence of and Factors Associated With Chronic Obstructive Pulmonary Disease in a Rapidly Aging Society: Korea National Health and Nutrition Examination Survey 2015-2019

BACKGROUND

The prevalence of chronic obstructive pulmonary disease (COPD) increases with age, and aging is an important risk factor for COPD development. In the era of global aging, demographic information about the prevalence of and factors associated with COPD are important to establish COPD care plans. However, limited information is available in rapidly aging societies, including Korea.

METHODS

We conducted a cross-sectional observational study using Korea National Health and Nutrition Examination Survey data from 2015-2019. We included 15,613 participants and analyzed trends of and factors associated with COPD.

RESULTS

During the study period, the overall prevalence of COPD was 12.9%. Over five years, the yearly prevalence of COPD was fairly constant, ranging from 11.5% to 13.6%. Among individuals aged ≥ 70 years, nearly one-third met COPD diagnostic criteria. In the multivariable analysis, age 70 years or older was the most strong factor associated with COPD (adjusted odds ratio [aOR], 17.86; 95% confidence interval [CI], 14.16-22.52; compared with age 40-49), followed by asthma (aOR, 3.39; 95% CI, 2.44-4.71), male sex (aOR, 2.64; 95% CI, 2.18-3.19), and current smokers (aOR, 2.60; 95% CI, 2.08-3.25). Additionally, ex-smokers, low income, decreased forced expiratory volume in 1 second %pred, and a history of pulmonary tuberculosis were associated with COPD. On the other hand, body mass index (BMI) ≥ 25 kg/m² (aOR, 0.62; 95% CI, 0.54-0.71; compared with BMI 18.5-24.9 kg/m²) had an inverse association with COPD.

CONCLUSION

Recent trends in the prevalence of COPD in South Korea are relatively stable. Approximately one-third of participants aged 70 years and older had COPD. Aging was the most important factor associated with COPD.

Treatment patterns and cost of exacerbations in patients with chronic obstructive pulmonary disease using multiple inhaler triple therapy in South Korea

Background

Multiple inhaler triple therapy (MITT), comprising inhaled corticosteroids (ICS), long-acting beta-agonists (LABA), and long-acting muscarinic antagonists (LAMA), has been used as an escalation treatment for patients with chronic obstructive pulmonary disease (COPD). However, real-world use of MITT has not been investigated in Asia, including South Korea. This study reports baseline characteristics of patients with COPD initiated on MITT in South Korea, and their treatment patterns. Healthcare resource utilization (HRU) and costs associated with COPD exacerbations following MITT initiation were also assessed.

Methods

This was a retrospective cohort study using the South Korea National Health Insurance database (2014–2018). Included patients were ≥ 40 years, had a COPD diagnosis, were newly initiated on MITT and had ≥ 12 months’ data both before (baseline) and after index date (the first day with overlapping supply of all MITT components). Treatment immediately before initiation and immediately following discontinuation of MITT were identified, and proportion of days covered (PDC) by MITT was calculated. HRU and costs (per person per year [PPPY]) associated with exacerbations were identified following MITT initiation; costs were calculated using the average 2020 exchange rate (0.0008 USD/KRW).

Results

Among 37,400 patients, the mean age was 69 (SD 10) years and 73% were males; 56% had ≥ 1 COPD exacerbation during the baseline period, with a mean of 2 (SD 5) events/year. ICS/LABA was the most frequent regimen prescribed immediately before initiation (37%) and immediately following discontinuation (41% of 34,264 patients) of MITT. At 3, 6, and 12 months from treatment initiation, mean PDC was 81%, 63% and 49%, respectively; median treatment duration was 102 days. The mean (95% confidence interval [CI]) number of total visits for severe COPD exacerbations was 0.77 PPPY (0.75–0.78); mean PPPY total healthcare costs were 2093 USD.

Conclusions

Patients with COPD in South Korea experienced frequent exacerbations prior to MITT, and PDC by MITT was low. Patients may benefit from early optimization of COPD therapy, and greater emphasis on adherence to inhaled COPD therapy. Severe exacerbations were found to incur substantial costs; treatment alternatives that can reduce the rate of severe exacerbations are likely to minimize healthcare costs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02136-0.

Nonadherence to health promotion depending on chronic obstructive pulmonary disease severity

BACKGROUND

Nonadherence to recommended health behaviors reportedly correlates with the prevalence and health outcomes of COPD, but the factors contributing to multiple health promotions are not well understood.

OBJECTIVE

To examine the factors associated with nonadherence to health behaviors, specifically focusing on COPD severity.

METHODS

We conducted a secondary data analysis with data from the 2016-2019 Korea National Health and Nutrition Examination Survey. The analyzed data were from 1,627 individuals aged over 40 years who had a FEV1/FVC ratio < 70% measured via spirometer. In this study, nonadherence to health behaviors is the sum of seven health-promoting behaviors in terms of smoking cessation, alcohol abstinence, regular exercise, weight control, recommended sleep time, influenza vaccination, and medical check-up.

RESULTS

COPD patients' nonadherence to health behaviors was significantly associated with comorbidity (p=0.017), stress (p=0.002), and COPD severity (moderate, severe; p=0.010, p=0.039, respectively). In addition, the moderate and severe COPD groups showed a higher nonadherence rate than the mild COPD group. Specifically, nonadherence to weight control was the most significantly different behavior according to COPD severity levels, based on the GOLD classification of airflow limitation.

CONCLUSION

Our study findings support that those with higher levels of stress, comorbidities, and severe disease conditions are less likely to adhere to health behaviors. Thus, healthcare providers and policymakers should provide tailored approaches according to COPD severity to educate and support appropriate health behaviors for individuals with COPD.

Effects of exposure to ambient air pollution on pulmonary function impairment in South Korea: Korea National Health and Nutritional Examination Survey

OBJECTIVES

This study aimed to investigate the association between pulmonary function and air pollution using 2007–2017 data from the Korea National Health and Nutrition Examination Survey, a nationwide cross-sectional representative survey.

METHODS

A total of 27,378 participants that had sampling weights from a complex sample survey were included in this study. Using the data for forced expiratory volume in 1 second and forced vital capacity, the participants with pulmonary function impairment were classified according to the criteria of restrictive lung disease and chronic obstructive pulmonary disease (COPD). Exposure to ambient air pollution was estimated using the Community Multiscale Air Quality model. Multivariate linear and logistic regression analyses with complex samples were used to determine the associations between pulmonary function and air pollution after adjusting for covariates.

RESULTS

In total, 13.2% of the participants aged >40 years had COPD, and 10.7% were classified as being in the restrictive lung disease group. According to the multivariate logistic regression model, the odds ratios for the fourth quartiles of particulate matter less than 10 μm in diameter (PM₁₀), particulate matter less than 2.5 μm in diameter (PM_2.5) and carbon monoxide (CO) with a 2-year lag period were 1.203 (95% confidence interval [CI], 1.036 to 1.396), 1.283 (95% CI, 1.101 to1.495), and 1.292 (95% CI, 1.110 to 1.504), respectively, using the restrictive lung disease group as an event after adjusting for covariates in the complex sample.

CONCLUSIONS

Long-term exposure to PM₁₀, PM_2.5, and CO was significantly associated with pulmonary function, especially restrictive lung disease.

Sirtuin 3 Ameliorates Lung Senescence and Improves Type II Alveolar Epithelial Cell Function by Enhancing the FoxO3a-Dependent Antioxidant Defense Mechanism

Lung aging alters the intrinsic structure of the lung and pulmonary surfactant system and increases the mortality and morbidity due to respiratory diseases in elderly individuals. We hypothesized that lung aging results from an insufficiency of type II alveolar epithelial cells (AECIIs) in the lung tissue. Sirtuin 3 (SIRT3) is a member of the sirtuin family of proteins that promote longevity in many organisms. Increased SIRT3 expression has been linked to an extended life span in humans. Hence, we speculated that the overexpression of SIRT3 may help to ameliorate lung senescence and improve AECII function. AECIIs were isolated from young and old patients with pneumothorax caused by pulmonary bullae. The expression of SIRT3, manganese superoxide dismutase, and catalase, as well as cell function and senescence indicators of young and old AECIIs, was measured before and after SIRT3 overexpression. After SIRT3 overexpression, the aged state of old AECIIs improved, and antiapoptotic activity, proliferation, and secretion were dramatically enhanced. Surfactant protein C (SPC), which is secreted by AECIIs, reduces alveolar surface tension, repairs the alveolar structure, and regulates inflammation. SPC deficiency in patients is associated with increased inflammation and delayed repair. SIRT3 deacetylated forkhead box O3a, thereby protecting mitochondria from oxidative stress and improving cell function and the senescent state of old AECIIs. These findings provide a possible direction for aging-delaying therapies and interventions for diseases of the respiratory system.

COPD Guidelines in the Asia-Pacific Regions: Similarities and Differences

Chronic obstructive pulmonary disease (COPD) is a preventable and treatable disease that is associated with significant morbidity and mortality, giving rise to an enormous social and economic burden. The Global Strategy for the Diagnosis, Management and Prevention of Chronic Obstructive Pulmonary Disease (GOLD) report is one of the most frequently used documents for managing COPD patients worldwide. A survey was conducted across country-level members of Asia-Pacific Society of Respiratory (APSR) for collecting an updated version of local COPD guidelines, which were implemented in each country. This is the first report to summarize the similarities and differences among the COPD guidelines across the Asia-Pacific region. The degree of airflow limitation, assessment of COPD severity, management, and pharmacologic therapy of stable COPD will be reviewed in this report.

Comorbidities and Factors Determining Medical Expenses and Length of Stay for Admitted COVID-19 Patients in Korea

Purpose

No previous investigations of coronavirus disease 2019 (COVID-19) have estimated medical expenses, length of stay, or factors influencing them using administrative datasets. This study aims to fill this research gap for the Republic of Korea, which has over 10,000 confirmed COVID-19 cases.

Patients and Methods

Using the nationwide health insurance claims data of 7590 confirmed COVID-19 patients, we estimated average medical expenses and inpatient days per patient, and performed multivariate negative binomial, and gamma regressions to determine influencing factors for higher outcomes.

Results

According to the results, COVID-19 patients with history of ICU admission, chest CT imaging, lopinavir/ritonavir and hydroxychloroquine use stayed longer in the hospital and spent more on medical expenses, and anti-hypertensive drugs were insignificantly associated with the outcomes. Female patients stayed longer in the hospital in the over 65 age group but spent less in medical expenses that the 20-39 group. In the 40-69 age group, patients with health insurance stayed longer in the hospital and spent more on medical expenses than those aged over 65 years. Comorbidities did not affect outcomes in most age groups.

Conclusion

In summary, contrary to popular beliefs, medical expenses and length of hospitalization were mostly influenced by age, and not by comorbidities, anti-viral, or anti-hypertensive drugs. Thus, responses should focus on infection prevention and control rather than clinical countermeasures.

Association of Body Mass Index with Risk of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

The association between body mass index (BMI) and chronic obstructive pulmonary disease (COPD) remains controversial. Therefore, a meta-analysis was conducted to further evaluate the relationship. A comprehensive literature search was performed in PubMed, Web of Science, EMBASE, China National Knowledge Infrastructure (CNKI), and Wanfang databases to identify eligible articles until July 15, 2020. Random effect model (REM) was used to compute the pooled results with 95% confidence intervals (CIs). We conducted meta-regression and subgroup analysis to explore potential sources of heterogeneity. Publication bias was evaluated by funnel plots and Egger's test. Thirty articles with 1,578,449 participants were included in the meta-analysis. The pooled OR of COPD was 1.96 (95% CI: 1.78-2.17) for the underweight group, 0.80 (95% CI: 0.73-0.87) for overweight group, and 0.86 (95% CI: 0.73-1.02) for obesity group. After further excluding 5 studies of high between-study heterogeneity in sensitivity analysis, the pooled OR of COPD was 0.77 (95% CI: 0.68-0.86) for the obesity group. This meta-analysis indicated that BMI was associated with COPD. Specifically, underweight might increase the risk of COPD; overweight and obesity might reduce the risk of COPD.

Direct Switch from Tiotropium to Indacaterol/Glycopyrronium in Chronic Obstructive Pulmonary Disease Patients in Korea

Background

Many chronic obstructive pulmonary disease (COPD) patients receiving monotherapy continue to experience symptoms, exacerbations and poor quality of life. This study aimed to assess the efficacy and safety of direct switch from once-daily tiotropium (TIO) 18 μg to indacaterol/glycopyrronium (IND/GLY) 110/50 μg once daily in COPD patients in Korea.

Methods

This was a randomized, open-label, parallel group, 12-week trial in mild-to-moderate COPD patients who received TIO 18 μg once daily for ≥12 weeks prior to study initiation. Patients aged ≥40 years, with predicted post-bronchodilator forced expiratory volume in 1 second (FEV₁) ≥50%, post-bronchodilator FEV₁/forced vital capacity <0.7 and smoking history of ≥10 pack-years were included. Eligible patients were randomized in a 1:1 ratio to either IND/GLY or TIO. The primary objective was to demonstrate superiority of IND/GLY over TIO in pre-dose trough FEV₁ at week 12. Secondary endpoints included transition dyspnea index (TDI) focal score, COPD assessment test (CAT) total score, and rescue medication use following the 12-week treatment, and safety assessment.

Results

Of the 442 patients screened, 379 were randomized and 347 completed the study. IND/GLY demonstrated superiority in pre-dose trough FEV₁ versus TIO at week 12 (least squares mean treatment difference [Δ], 50 mL; p=0.013). Also, numerical improvements were observed with IND/GLY in the TDI focal score (Δ, 0.31), CAT total score (Δ, −0.81), and rescue medication use (Δ, −0.09 puffs/day). Both treatments were well tolerated by patients.

Conclusion

A direct switch from TIO to IND/GLY provided improvements in lung function and other patient-reported outcomes with an acceptable safety profile in patients with mild-to-moderate airflow limitation.

Progression of erectile function in men with chronic obstructive pulmonary disease: a cohort study

BACKGROUND

Although sexual function is a quality of life aspect that is markedly affected in males with chronic obstructive pulmonary disease (COPD), this topic has not attracted much attention and research on this matter is lacking. In this study, we investigated longitudinal changes in the erectile function of men with COPD in order to identify latent groups and influencing factors.

METHODS

A total of 185 men with COPD from the Korean Obstructive Lung Disease study, which was conducted from 2005 to 2013, were analyzed in this study. Data on their erectile function, based on the International Index of Erectile Function-5, were collected over a period of 4 years. Growth mixture modeling and logistic regression analysis were used to determine the factors predicting distinct erectile function changes over time.

RESULTS

Overall, subjects' erectile function slightly improved in the first year and then gradually worsened over time. Using growth mixture modeling, we identified four distinct latent groups, which we labeled as follows: "consistently maintained normal erectile function" (9.7%), "rapidly worsened and then rapidly improved" (9.2%), "gradually improved in the early stage and then gradually worsened" (36.8%), and "consistently maintained poor erectile function" (44.3%). Progression of erectile function was significantly associated with age, economic status, and self-rated health status.

CONCLUSIONS

This suggests that comprehensive patient care involving the management of COPD as well as erectile dysfunction in patients with chronic respiratory disease is important from a prophylactic perspective and should be developed in accordance with the characteristics of the disease process.

Alveolar Differentiation Potency of Human Distal Airway Stem Cells Is Associated with Pulmonary Pathological Conditions

Background

This study is aimed at characterizing the human distal airway stem cells (DASCs) and assessing their therapeutic potential in patients with chronic, degenerative lung diseases. These findings will provide a comprehensive understanding for further clinical applications utilizing autologous airway stem cells as therapeutic intervention in respiratory diseases.

Methods

DASCs were isolated from healthy subjects or patients diagnosed with bronchiectasis, chronic obstructive pulmonary diseases (COPD), or interstitial lung disease (ILD). Differentiation capacity, a key property of the stem cells, was studied using a novel monolayer differentiation system. The differentiated cells were evaluated for alveolar and bronchial cell marker expression, and the quantified expression level of differentiated cells was further examined for their relationship with age and pulmonary function of the subjects.

Results and Conclusions

Differentiation of DASCs and tracheal stem cells (TSCs) yielded an alveolus-like structure and a tube-shaped structure, respectively, with distinct marker gene expression. Additionally, single-cell-derived clones showed diverse differentiation fates, even if the clones arise from identical or different individuals. More importantly, the alveolar differentiation potency was higher in DASCs derived from patients than from healthy people. The differentiation efficiency of DASCs also correlates with age in patients with bronchiectasis and ILD.

Factors affecting the development of airflow limitation among South Korean smokers

INTRODUCTION

Considering that only some and not all smokers develop chronic obstructive pulmonary disease (COPD), there may be other factors responsible for the development of COPD among smokers. Previous researchers have reported that ethnicity could be one of factors associated with the development of COPD. This study aimed to examine the factors associated with the development of airflow limitation, suggestive of having COPD, among Korean smokers using data from the Korea National Health and Nutrition Examination Survey conducted over the past 3 years.

METHODS

A total of 2569 current and former smokers ≥40 years of age were included. Most studies exploring risk factors for COPD have compared smokers and non-smokers with smoking as only one of the independent variables. In this study, we took a different approach, studying only smokers and comparing those with or without airflow limitation.

RESULTS

The prevalence of airflow limitation among the study participants was 19.2% and 22.1% in current and former smokers, respectively. There was no significant correlation between the severity of airflow limitation and total lifetime smoking amount. Among the many variables examined, only age, male gender and total lifetime smoking amount (pack-years) were significant factors associated with the development of cigarette smoke-induced airflow limitation.

CONSLUSIONS

Older Korean men who are heavy smokers may be at a higher risk of developing COPD. Our findings support the importance of smoking cessation as the best way to prevent the development of COPD.

PRISMA-compliant meta-analysis: association of metabolic syndrome and its components with the risk of chronic obstructive pulmonary disease

A preferred reporting items for systematic reviews and meta-analyses-compliant meta-analysis was conducted to test the association of metabolic syndrome and its components with the risk of chronic obstructive pulmonary disease (COPD) based on observational studies. Literature retrieval, article selection and data extraction were done by two researchers independently. Total 16 articles (20 independent studies) were analyzed with 3915 COPD patients and 25,790 control participants. Overall analysis indicated that metabolic syndrome was significantly associated with 1.53-fold (95% confidence interval [CI]: 1.23–1.9, P<0.001) increased risk of COPD, with moderate heterogeneity (I² = 74.3%). Of four metabolic components, hypertension was significantly associated with 1.55-fold (95% CI: 1.14–2.11, P=0.005) increased risk, and averaged levels of systolic blood pressure (weighted mean difference [WMD] = 3.626 mmHg, 95% CI: 1.537–5.714, P<0.001) and glucose (WMD = 2.976 mmol/l, 95% CI: 0.141–5.812; P=0.04) were significantly higher in COPD patients than in control participants, yet that of body mass index (WMD = −1.463 kg/m², 95% CI: −2.716 to −0.211, P=0.022) were significantly lower. Gender, race, source of control participants, matched status and sample size were identified as accountable factors for significant heterogeneity. Altogether, the presence of metabolic syndrome, especially its component hypertension, was associated with significantly increased risk of COPD.

The Association between Socioeconomic Status and Adherence to Health Check-up in Korean Adults, Based on the 2010-2012 Korean National Health and Nutrition Examination Survey

Background

We investigated the association between socioeconomic status and adherence to health check-ups in a Korean population aged 40 years or older.

Methods

This cross-sectional study included 12,311 participants who participated in the 2010–2012 Korean National Health and Nutrition Examination Survey. Self-reported questionnaires were used to assess each participant's socioeconomic status (household income, occupation, and education) and adherence to health check-ups.

Results

Men with a higher income (highest vs. lowest: odds ratio [OR], 1.799; 95% confidence interval [CI], 1.296–2.497) and men with a higher education level (≥12 vs. <6 years: OR, 1.488; 95% CI, 1.078–2.054) and office workers compared with manual workers (men: OR, 1.431; 95% CI, 1.077–1.902; women: OR, 1.783; 95% CI, 1.256–2.532) appeared to undergo more health check-ups. In particular, men and women with a higher income and education appeared more likely to undergo opportunistic health check-ups (men: highest vs. lowest income: OR, 2.380; 95% CI, 1.218–4.653; ≥12 vs. <6 years education: OR, 2.121; 95% CI, 1.142–3.936; women: highest vs. lowest income: OR, 4.042; 95% CI, 2.239–7.297; ≥12 vs. <6 years education: OR, 2.475; 95% CI, 1.283–4.775).

Conclusion

A higher socioeconomic status was associated with a higher rate of participation in health check-ups. More efforts are needed to identify the factors associated with disparity in adherence to health check-ups.

Association of Time to First Morning Cigarette and Chronic Obstructive Pulmonary Disease Measured by Spirometry in Current Smokers

Background

Time to first cigarette after waking is an indicator of nicotine dependence. We aimed to identify the association between time to first cigarette and spirometry-proven obstructive respiratory impairment, especially chronic obstructive pulmonary disease, in current smokers.

Methods

We included 392 subjects who visited the comprehensive medical examination center of Hallym University Sacred Heart Hospital between July 2014 and September 2015. Subjects with lung disease or anemia were excluded. Obstructive pulmonary impairment was defined as <70% of the predicted value of forced expiratory volume in 1 second/forced vital capacity. Subjects were classified into the early (≤30 minutes) and late (>30 minutes) groups based on the time to first cigarette. Logistic regression and linear regression analyses were used for data analysis.

Results

Ninety-eight subjects (25%) were classified into the early group. After adjusting for smoking behaviors (cigarettes per day and smoking duration), socioeconomic status (education and income), age, and physical activity, an early time to first cigarette was found to be associated with an increased risk of obstructive pulmonary impairment measured using spirometry (adjusted odds ratio, 2.84; 95% confidence interval, 1.22–6.61).

Conclusion

Compared to current smokers with a late time to first cigarette, those with an early time to first cigarette had a higher risk of obstructive pulmonary impairment, especially chronic obstructive pulmonary disease. Classifying smoking-related behaviors, especially time to first cigarette, may help target clinical screening for chronic obstructive pulmonary disease.

Prevalence and risk factors of airflow limitation in a Mongolian population in Ulaanbaatar: Cross-sectional studies

The burden of chronic obstructive pulmonary disease (COPD) is expected to increase in the coming decades. In Ulaanbaatar, Mongolia, air pollution, which has been suggested to correlate with COPD, is a growing concern. However, the COPD prevalence in Ulaanbaatar is currently unknown. This study aims to estimate the prevalence of airflow limitation and investigate the association between airflow limitation and putative risk factors in the Mongolian population. Five cross-sectional studies were carried out in Ulaanbaatar. Administration of a self-completed questionnaire, body measurements, and medical examination including spirometry were performed in 746 subjects aged 40 to 79 years living in Ulaanbaatar. The age- and sex-standardized prevalence of airflow limitation in Ulaanbaatar varied widely from 4.0 to 10.9% depending on the criteria for asthma. Age, body mass index (BMI), and smoking habit were independent predictors for airflow limitation while residential area and household fuel type were not significant. In conclusion, prevalence of putative COPD was 10.0% when subjects with physician-diagnosed asthma were excluded from COPD. Older age, lower BMI, and current smoking status were putative risk factors for airflow limitation. This prevalence was consistent with reports from Asian countries.

Changes in the prevalence of COPD in Korea between 2001 and 2011 in the KNHANES data

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a serious public health problem. Understanding the longitudinal trend in prevalence is important for characterizing the burden of COPD and planning health services.

METHODS

We analyzed the prevalence of airflow obstruction between 2001 and 2011 using data from Korean National Health and Nutritional Examination Surveys (2001, n = 2217; 2011, n = 3101). Participants >40 years of age with an FEV₁/FVC <0.7 were defined as having COPD. We used data from the Population and Housing Census, which was conducted by Statistics Korea in 2010, to compare the prevalence of COPD after standardizing by age.

RESULTS

The crude prevalence of COPD was not significantly different between 2001 and 2011 (2001, 13.0%; 2011, 13.2%), but the age-standardized prevalence of COPD decreased significantly over the 10-year period (2001, 15.7%; 2011, 12.4%). While significant decreases were observed for ex-smokers and current smokers, significant increases were noted for subjects who smoked <20 pack-years and those with a BMI ≤18.5 kg/m². The prevalence of mild and severe COPD decreased (2001, mild 8.5%, severe 1.4%; 2011, mild 5.4%, severe 0.5%), while the prevalence of moderate COPD increased (2001, 5.7%; 2011, 6.4%) after age standardization.

CONCLUSIONS

We report a reduction in the age-standardized prevalence of COPD in Korea from 2001 to 2011. Continued surveillance and early prevention are required because the socioeconomic burden of COPD remains substantial.

Safety and Effectiveness of Indacaterol in Chronic Obstructive Pulmonary Disease Patients in South Korea

BACKGROUND

Inhaled indacaterol (Onbrez Breezhaler), a long-acting β₂-agonist, is approved in over 100 countries, including South Korea, as a once-daily bronchodilator for maintenance and treatment of chronic obstructive pulmonary disease (COPD). Here, we present an interim analysis of a post-marketing surveillance study conducted to evaluate the real-world safety and effectiveness of indacaterol in the Korean population.

METHODS

This was an open-label, observational, prospective study in which COPD patients, who were newly prescribed with indacaterol (150 or 300 µg), were evaluated for 12 or 24 weeks. Safety was assessed based on the incidence rates of adverse events (AEs) and serious adverse events (SAEs). Effectiveness was evaluated based on physician's assessment by considering changes in symptoms and lung function, if the values of forced expiratory volume in 1 second were available.

RESULTS

Safety data were analyzed in 1,016 patients of the 1,043 enrolled COPD patients receiving indacaterol, and 784 patients were included for the effectiveness analysis. AEs were reported in 228 (22.44%) patients, while 98 (9.65%) patients reported SAEs. The COPD condition improved in 348 patients (44.4%), while the condition was maintained in 396 patients (50.5%), and only 40 patients (5.1%) exhibited worsening of ailment as compared with baseline. During the treatment period, 90 patients were hospitalized while nine patients died. All deaths were assessed to be not related to the study drug by the investigator.

CONCLUSION

In real-life clinical practice in South Korea, indacaterol was well tolerated in COPD patients, and can be regarded as an effective option for their maintenance treatment.

Burden of Disease Attributable to Smoking in Korea

Smoking is one of the major health threats and is highly prevalent in Korea. This study quantifies the burden of disease (BOD) resulting from smoking by using the most reliable national statistics of Korea. We followed Global Burden of Disease Study (GBD) 2013 methodology for estimating BOD attributable to smoking. Population attributable fraction was calculated for all diseases and multiplied by disability-adjusted life years (DALYs) to obtain BOD by each disease. Total burden of smoking in Korea was 1 368 072 DALYs (38 per 1000); 68% of the disease burden was in males and 32% in females. The highest percentage of burden was a result of chronic obstructive pulmonary disease in both genders. BOD was highest in the 70- to 74-year-old age group. Smoking burden is substantial in Korea, especially among the elderly population. Tailored health plans for each gender and age should be formulated, and smoking-related burden should be continuously monitored to evaluate the extent of hazard and create priority settings.

Meta-analysis approach to study the prevalence of chronic obstructive pulmonary disease among current, former and non-smokers

Comparative risk assessment for Chronic Obstructive Pulmonary Disease (COPD) among current, former and non-smokers categories remains controversial and not studied in detail. We conducted a meta-analysis to summarize all the relevant published studies on this topic and to update the association between smoking and prevalence of COPD in current, former and non-smokers. Identification, screening, eligibility and inclusion of articles for the study were conducted as per the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Quality assessment of included studies was undertaken using a scoring sheet. Meta-analysis after the final synthesis of the selected studies was performed using the STATA and Comprehensive Meta-Analysis (CMA) software. Estimates from forty two independent studies reporting 547,391 individuals were identified. Twenty two studies were conducted in Europe, nine in America and ten in Asia and one from New Zealand. The meta-analysis showed that the prevalence of COPD was significantly higher in current smokers compared with former and non-smokers. However, owing to large heterogeneity among the estimates obtained from the studies, stratification was done with respect to continent, diagnostic criteria of COPD and study design which also showed similar results. The stratified analysis also revealed similar trend of results with prevalence of COPD being higher in current smokers as compared to former and non-smokers. The present meta-analysis highlights the positive association between smoking and COPD prevalence. There is an urgent need to implement more effective policies towards the restriction of tobacco use, to reduce the burden of COPD.